Apparatus for reproducing and recording sound



Feb. 17, 1942. s. YERKOVICH 2,273,391

APPARATUS FOR REPRODUCI NG AND RECORDING SOUND I Filed June 19, 1939 2Sheets-Sheet 1 m 7 L J INVEN TOR 5/)110/2 YerAar/ck ATTO R NEY Feb. 17,1942. I s. YERKQVICH 2,273,391

APPARATUS FOR REPRODUCING AND RECORDING SOUND Filed June 19, 1939 2Sheets-Sheei 2 INVENTOR 7? 0/2 )rfo V/c/I BY W ATTORNEY Patented Feb.17,1942 i p Y UNITE-D1- STATE APPARATUS FOR nErnonUcmG AND neconnnvcSOUND 7 Simon Yerko'vlch, Lcs Angeles, flalif assignor to UnitedAcoustlgraph-Corporation, Los Angeles,

CaliL, a corporation of Nevada Application June 19, 1935}, Serial No.279,849

11 Claims.

This invention relates to sound recording and reproducing apparatus, andmore particularly to apparatus that incorporates a stylus in contactwith a record or a record blank.

In such apparatus, the blank for receiving the sound record may be inthe form of a thin' endless flexible loop or band, upon which thevibrating stylus impresses or cuts the undulations that correspond tothe sound. In reproducing,

the stylus point is permitted to follow the record grooves freely, and'such movement causes corresponding current variations in a translatingCllOllliL' In both recording and reproducing, the

ture, the apparatus embodying the invention is effective to control theoperation fof the stylus-for bothrecording and reproduction purposes.

- This invention possesses many otherfadvan-f tages, and has otherobjects which may be made more easilyapparent from a consideration ofone stylus must be advanced in a direction transverse to the motionofthe record or the blank. This may. conveniently be accomplished by alead screw, engaging a carriage upon which the stylus andits associatedmechanismis mounted.

It is one of. the objects of this invention to i make it possible to usethe same stylus and carriage for recording as well as for reproduction.For this purpose, the stylus is provided with a blunt point suchwas a.sapphire point, which impresses the record undulations in a blankwithout cutting it, and which can readily follow the record grooves forreproduction, without undue wear.

, It is necessary, for the purposes of recording, that the styluspointform the record grooves as the carriage advances, and that thestylus be so mounted as to make'it possible to exert an adequatepressure on the blank by the stylus point. Yet when it is desired toreproduce the record, the stylus must be left quite unrestrained so asto enable it effectively to follow the previ-- ously' formedundulationa' other object of this invention to provide a mechanism suchthat these differing requirements for recording and reproducing may beobtainedat will, as by a convenient adjustment or control.

n One of the important features of the recording .and reproducing stylusstructure is that the stylus can be vibratedto cause considerablepressure for recording, and-the stylus yet is maintained against.appreciable movement under. the

forces acting on the stylus that are} useful for producing the record;and ,yet, when the stylus. is used for reproduction purposes, it issufliciently yielding to permit the stylus. to' follow the. recordgrooves and undulations; rhea-structure by the aid ofISflrCCDIQPMQdiS'dGSCPibGd Bind It is therefore an- 5 a claimed-in a qpnd li evaluation. entitledv cording and jreproducing head, Serial Nofrecord.

Name, mf qnjunctionwith suchastylus 'struo: 5 5

embodimentof the invention. Forthis purpose there is shown. a formin thedrawings'accompanying and forming part of the'pre'sent'specification,This form willno'wbe described indetail, illustrating the generalprinciples oftithe invention; but itis to be understood that detaileddescription is not to be taken in a-limiting sense, since the scope ofthis invention is best defined by the appendedclaims, a

Referring to the drawings:

Figure 1 is a view, partly in'longitudinal section, of an apparatusincorporating the invention and shown as in use for'reproducing;

Fig. 2 is a side view of the apparatus illustrated in Fig. 1. Y

Figs. 3, 4 and 5 are sectional -views taken respectively along theplanes 3-3, H and 5- 5 of Fig. 1; r

Fig. 6 is a fragmentary view similar to Fig, 1, illustrating theapparatus in use for recording;

Fig. 7 is a top plan view of the mounting structure of the stylusutilized in connection with the In the present instance, the recordmember l is shown as a thin, flexible loop adapted to be .disposed overthe. rollers 2 and} appropriately -mounted and arranged to move therecord member past a vibratory stylus-l. In the recording, as well as inthe reproducing position, the tip of the stylus, which may be formedofsome, gem point, such as sapphire, may bepla'ced against .the recordmember I opposite an anvil member 5 (Figs. 1 and 6) disposed .back ofthe recor'd'member I and capable of being turnedto the "active 3position illustrated in these i -The stylus 4 is incorporatedgenerally'in' a stylus structure .or head structure 6 in detail in theaforementioned application filed in the name ofB emard F. McNamee.general it may be stated for the present stylus structure provides forthe. vibration ofthe, stylus 4 about an axis I, causing the stylusl tomake a lateral record, or to bervibrated aboutfthe axis 1 by playing ina groove carryingsucha lateral In reproducing the sound, the stylu verseto the surface I.

6 is intended to be nioved at a substantially uniform rate in adirection transverse of the exposed surface of the record member This isordinarily accomplished by the aid of a carriage structure U advancedfor example as by a threaded lead screw 8 (Figs. 1 and 2). This leadscrew may be appropriately supported for rotation as in the side members9 and ID of a stationary frame. It may be rotated by any appropriatesource of motion such as a small electric motor (not shown). .Thecarriage structure U (Figs. 1, 2 and 3) is arranged to be moved by thelead screw 8 as by the aid of a half nut |2 fastened to carriage Thesides of the carriage H are provided with appropriate apertures for thepassage of a stationary guide rod |3 appropriately supported by theframe members 9 and ID. A lower guide rod l4 of similar structure toguide rod 3 is engaged within the slots |5 in the lower portion of thecarriage The rods 13 and I4 thus restrain the carriage I from anymovement other than in a direction parallel with the axes of the guiderods I3 and I4.

It is essential when the stylus 4 is used for reproduction that it bequite free to follow the record groove and its lateral undulations. Forthis purpose it is desirable so to mount the stylus 4 as to permit itto'move in a direction transverseto the record surface. At the same time'the stylus 4 should be so mounted that it is caused to vibrate aboutits own axis 1 through the minute amplitudes corresponding to theundulations in the sides of the record groove. A force must also beprovided for urging the stylus point into the groove. By the aid of thepresent mounting illustrated in Figs. 1, 2, 3 and 4, these requirementsare adequately provided for.

. Thus the'stylus structure 6 is shown as mounted on top of a supportingmember 80 having a rearwardly extending portion i8, as well asdownwardly directed arms I! and Hi. These arms Ii and l 8 are shown asprovided with headless conical pointed pivot screws l9 and 2G, by theaid of which the supporting member 80 is pivotally mounted on an axisparallel to the surface of the record member I. For this purposefthepivot screws l9 and 28 engage a block 2| extending upwardly between thearms ii and I8. This block 2| is provided with downwardly directed arms22 and 23. pivot for the structure 6 about an axis trans- For thispurpose there are shown a pair of headless conical pivot screws 24 and25 threaded respectively through the arms 26 and 21 of a bracket 28.This bracket 28 is appropriately supported on top of the carriageWithout further provisions, it is seen that the structure 6 has freedomof motion about a pivot 29-parallel to the record surface i, as well asabout a pivot 33 transverse to the record surface I. Accordingly, as thecarriage H is advanced by the lead screw 8, the structure 3 can accom-'modate itself to the vagaries of the groove in the record member of theparts is such that the minute undulations in the walls of the groovecause the stylus to be vibrated about its own axis 7, and thereby affectanappropriate pickup circuit. One of the terminals for this circuit isindicated at 3| in Fig. l.

A light resilient force is provided for keeping the stylus 4 in contactwith the groove same time a light, resilient force is also providedtending to keep the structure 6 centralized about These arms provide aAt the same time the inertia an angle bracket 32 fastened to the lefthand At the the transverse axis 30. The manner in which this isaccomplished will now be described.

Thus the arm or extension |6 formed on the support is subjected to theupward pressure of a compression spring 8| (Figs. 1 and 2). The lowerend of this compression spring rests upon edge of carriage I I. Theupper end of the compression spring 8| carries a disk 33 disposedimmediately below the bottom of an adjusting screw 34 passing throughthe extension H5. The spring 8| thus urges the extension I6 upwardly,and

\ thereby the structure 6 about the axis 29 parallel to the surface ofthe record.

To provide the centralizing resilient force about the axis 30, use ismade of a bar spring 35. This bar spring 35, as shown most clearly inFig. 2, extends axially of the screw 34 and may be fixed therein. Itextends downwardlythrough the disk 33 and through the spring 8|, whichsurrounds the bar spring 35. The bracket 32 is provided with a largeclearance aperture 36 to permit passage of the bar spring therethrough,irrespective of the angular position of the support 80 about its axis29. The free or lower end of the bar spring is accommodated in a slot 3!formed in a bracket 38 attached adjacent the lower edge of the carriageThe slot 3'! extends in a direction parallel to the transverse axis 3|].By engagement of the lower end of the bar spring 35 with one or theother wall of the slot 31, this bar spring 35 is flexed by the forceexerted upon it whenever the structure 6 is urged away from a centralposition with respect to the axis 30. The force of the bar spring tendsto keep the structure 6 in a vertical position, but readily permits thestructure nevertheless to depart slightly from'this vertical position asrequired by the restraint imposed upon the stylus 4 by the walls of therecord groove.

These light resilient forces provided by the springs 8| and 35, whileessential for purposes of reproduction, should be altered during theprocess of recording with the same stylus 4. For

a recording purposes, for example, a much greater force should beexerted, urging the stylus 4 toward the recording surface; and thestructure-|5 must be restrained from any motion whatever about the axis33. In this way, sufficient forces may be caused to be exerted upon thestylus 4 for obtaining a requisite pressure not only to form the recordgroove, but also its lateral undulations.

A simple mechanism is provided for ensuring that during the process ofrecording these restraints and forces be properly proportioned.

Thus for example the restraint against motion about the axis 30 isaccomplished in the present instance by providing a cam member 39 (Figs.1, 3, 4 and 6). This cam member is shown as extending beneath the block2| and as supported on a rotary shaft 40, journaled in arms 4| and 42provided on the support 43. This support 63, as shown most clearly inFigs. 3 and 4, is supported upon the top surface of the carriage i. Theshaft 48 is restrained against axial movement as by the collars M and35.

The cam 33 is of general circular configuration: but at its top surfaceit has a flattened portion lofi' In the position of Figs. 1 and 3, thisflattened top portion $3 is substantially parallel with the lowersurface 6? of the block 29. It therefore is out of the path of movementof the block 2|, as block 25 pivots about the axis 3!].-

been rotated so that the circular surface of the cam now engages thebottom surface or pad 41 of the block 2|. Accordingly due to theengagement of thecylindrical surface of the cam 39 withthe surface 41,rotation about axis 30 is prevented.

Provision are made also, for the period'of recording, to supplement theresilient force of the spring 8|. For this purpose the lower. end of theextension [6 carries a flat spring 48 (Figs. 1, 4 and 6). The free endof the flat spring in the 'reproducing position of Fig. 1 is leftinoperative.

However, the free end of the spring may be engaged by a corner of'ablock 49 (Figs. 1. and '6) so as to impose a pressure upon thi free endand supplement the pressure of the spring 8|. ,In the reproducingposition, as shown most clearly in Fig. 5, the flat upper surface'ill ofthe block 49 clears f the lower end of the spring 48. One corner,however, maybe moved into contact with the fiat. spring uponrotation ofthe block 49 about an axis 5| of a shaft 52. This shaft52, as shown mostclearly in Fig. 2, is rotatably supported in the frame members 9 and w.The block 49 is splined't the shaft 52. It is arranged to be carriedalong with the carriage H, as by the uldof the projection 53, whichengages the arcuate slot 56 in the bottom of the block 39 (Fig. 5). Thisprojection 53 is shown as integral with the top of the carriage H.

The shaft 52 is provided at its left hand end with a, manipulating leveror handle 55 (Fig. 2). By the aid of this handle 55 the angular motionof the block 19 may be controlled. Preferably, however, the manipulationof handle 55 is also rendered eifectiveto rotate the cam shaft 618 forrestraining rotation about axis Z-ll. For this purpose the block .19, asshown most clearly in Figs. 1, 4 and 6, is provided with an upwardlyextending arm 56. The free end'of this arm is pivotaily joined to a link57]. The other end of link 5? is pivoted to an arm 523 (Fig. 2) fastenedto the shaft dd. Accordingly when the spline shaft 52 is rotated byhandle 55, not only is the block it rotated, but a rocking motion isalso imparted to the cam shaft till.

The adaptability of the stylus d for both recording and for reproductionis provided for by the aid of the structure disclosed in theaforementioned prior application filed in the name of Bernard F.McNameein Figs. 7 and 8 the essential elements of the stylus mountingare indi cated. Thus the stylus d is shown as accommodated in a saddleextension 5c of an armature, which'is made integral with a tubularsupport 5i.

This tubular support M is threaded at its upper end for engagement of athumb-screw 58 by the aid of which the stylus t may be clampedv withinthis saddle to. The tubular member 66 is journaled in resilient sleeves62 at the top and bottom of the supporting arms 83 and 615. Thesesupporting arms-- provide .sloping surfaces for the accommodation of thesleeves 62. These sleeves are clamped against thesloping. surfaces 'by acap 65 attached to the members 83 and 64. The armature which is made ofmagnetic material, is

' provided with a polar extension 66. This polar extension isaccommodated in an air gap 61 between the opposed polepieces B8 and 690i9. permanent magnet Ill (Figs. 1 and 6). The'coil ll surrounds thearmature. Current impulses may be induced in this coil during thereproducing period, as is well understood. For recording pur posescurrent impulses are passed to coil M for vibrating the armature and thestylus 4. Allthis has been detailed in the prior applicationhereinbefore referred to.

In order to restrain lateral movement of the support 6| parallel to therecord surface during the recording operation, while. yet permitting thestylus 4 to be, vibrated during reproducing operation, use is made of apair of bar springs 12 and 13. These bar springs extend in a directionlateral to the axis I and generally parallel to the record surface I.One end of each of the springs 12 and 13 is joined permanently to thetubular support 6!. The other end is adjustablyclamped to the bossesliand 16 respectively, as by the aid of the clamping members l1 and 18. Byappropriate adjustment of the springs 12 and 13 in the clamping members11 and 18, the stylus and its tubularsupport 6| can be accuratelycentered with respect to'the air gap 61. A strong restraintisreproducing impulses in connection with a surface of a record member,said structure including a stylus adapted to vibrate about an axis, acarriage movable parallel with said surface, means mounting thestructure on said carriage so that the structure may have freedom ofmotion toward and from the surface, as well as freedom of motion in adirection transverse to the surface with respect to the carriage, meansresiliently urging said structure toward said surface, and means forrestraining said structure against said transverse motion, as well asfor increasing the resilient force acting to urge said structure towardsaid surface, said means including a pair of simultaneously operablerotatable members on the car riage.

2. In a devicepf the character described, a stylus structure adapted forrecording and for reproducing impulses in connection with a surface of arecord member, a pivotal supporting means for the structure on an axisparallel to said surface, another pivotal support for the saidsupporting means on an axis transverse to the axis of the supportingmeans, a resilient means acting on the said supporting means for urgingsaid structure toward said surface, and means for imposing an additionalresilient forc on said supmeans for restraining movement of thestructure about said transverse axis, comprising a rotatablecarn'rneljnber on the carriage.

3. Ina device of the character described, a stylus structure adapted forrecording and for reproducing impulses in connection with a surface of arecord member,- and a mounting for the structure, comprising a carriagemovable parallel with said surface, a supporting means for saidstructure, means mounting said supporting means on said carriageincluding a pivot mounting said supporting means on an axis parallel tosaid surface, as well as a pivot mounting said supporting means on anaxis transverse to said surface, a spring urging the'supporting meanstoward the surface, and means actin to centralize the structure aboutthe said transverse axis with respect to the carriage, comprising a barspring interposed between the carriage and the mounting means.

4. In a device of the character described, a stylus structure adaptedforrecording and for reproducing impulses in connection with a. surfaceof a record member, and a mounting for the structure, comprising acarriage movable parallel with said surface, a supporting means for said.structure, means mounting said supporting 5. In adevice of thecharacter described, a

stylus structure adapted for recording and for reproducing impulses inconnection with a surface of a record member, and a mounting for thestructure, comprising a carriage movable parallel with said surface, asupporting means for said tructure, means mounting said supporting meanson said carriage including a pivot mounting said supporting means on anaxis parallel to said surface, as well as a pivot mounting saidsupporting means on an axis transverse to said surface, a spring urgingthe supporting means toward the surface, spring means arranged betweenthe supporting means and the carriage to centralize the structure aboutthe said transverse .axis, and means for restraining movement of thestructure mounting against movement about said transvers axis,comprising a, rotatable cam member interposed between the carriage and asurface of the mounting means.

6. Ina device of the character described, a stylus structure adapted forrecording and for reproducing impulses in connection with a surface of arecord member, and a mounting for the structure, comprising a,supporting means for said structure, a pivot mounting for saidsupporting means, on an axis parallel to said surface, means resilientlyurging said supporting means about said axis toward said surface, a flatspring attached at one end to the supporting means, and means includinga rotatable block for optionally engaging the free end of the flatspring, to increase the resilient force acting on the supporting means.

7. In a device of the character described, a stylus structure adaptedfor recording and for reproducing impulses in connection with a surfaceof a record member, a mounting means for said structure on axesrespectively parallel and transverse to the surface, a. spring operatingon the mounting means. and urging the structure about the parallel axisand toward said surface, a

fiat spring having one end attached to the mounting means, meansoptionally engaging the free end of the flat spring for increasing theforce urging the structure toward the surface, and means operatingoptionally to restrain the structure about the transverse axis,comprising a rotatable cam member interposed between the carriag and asurface of the mounting means.

8. In a deviceof the character described, a stylus structure adapted forrecording and for reproducing impulses in connection with a surface of arecord member, a mounting means for said structure on axes respectivelyparallel and transverse to the surface, a. spring operating on themounting means and urging the structure about the parallel axis andtoward said surface, a fiat spring having one end attached to themounting means, means optionally engaging the free end of the flatspring for increasing the force urging the structure toward the surface,means operating optionally to restrain the structure about thetransverse axis, and a connection between the liat spring engaging meansand said restraining means for simultaneously operating both of saidmeans.

9. In a device of the character described, a stylus structure adaptedfor recording and for reproducing impulses in connection with a surfaceof a, record member, a carriage movable parallel with said surface,means for mounting said structure on said carriage for movement about anaxis transverse to said surface, and means for centralizing saidstructure about said axis, comprising an elongated bar spring fixed atone end to said structure, and means forming a slot on the carriageextending in a direction parallel to the axis and into which the otherend of said bar spring enters.

10. In a device of the character described, a stylus structure adaptedfor recording and for reproducing impulses in connection with a surfaceof a record member, acarriage movable parallel with said surface, meanssupporting said structure on said carriage including means pivotallymounting the structure on an axis parallel to said surface, as well asabout an axis transverse to said surface, a bar spring carried by themeans mounting the structure about the-parallel axis, means carried bythe carriage forming a slot extending parallel to the transverse axisfor accommodating the free end of the bar spring, and a compressionspring surrounding the opposite end of the bar spring for urging thestructure toward the surface about the parallel axis.

11. In a device of the character described, a stylus structure adaptedfor recording and for reproducing impulses in connection with a surfaceof a record member, a carriage movable parallel with said surface, meanssupporting said structure on said carriage including means pivotallymounting the structure on an axis parallel to said surface, as well asabout an axis transverse to said surface, a bar spring carried by themeans mounting the structure about the parallel axis, means carried bythe carriage forming a slot extending parallel to the transverse axisfor accommodating the free end of the bar spring, a compression springsurrounding the opposite end of the bar spring for urging the structuretoward the surface about the parallel axis, and means for restrainingmovement of the structure about the transverse axis with respect to thecarriage as well as for increasing the resilient force urging saidstructure toward said surface, said means including a pair ofsimultaneously operable rotatable members on the carriage.

SIMON YERKOVICH.

